1. Field of the Invention
The present invention relates generally to machines and methods for the forming and sealing of envelopes, and more particularly to a machine for folding and inserting disks into floppy disk envelopes.
2. Description of the Prior Art
Envelopes used for encasing floppy disks are typically formed from a plastic film material having a non-woven fabric liner for protecting the disk media. Heretofore, such envelopes have been folded from precut envelope blanks which are transported individually among various folding and sealing stations on one or more folding machines. Frequently, a first folding apparatus is provided for transversely folding the envelope blank in half and sealing two flaps along the sides, leaving an open end opposite the transverse fold. The partially folded envelope is then taken to a second apparatus where the disk media is inserted and the end envelope flap folded and sealed.
The manipulation of single pre-cut envelope blanks presents a number of problems. The blanks must be advanced sequentially among various folding, disk insertion, and sealing stations, usually requiring complex systems of grippers and suction devices. Moreover, intermachine transfers are most often accomplished manually, requiring labor and often slowing down the folding process. The most serious drawback with the prior art folding machines, however, has been the difficulty in properly aligning the envelope blanks so that the dimensions of the resulting envelopes are precisely controlled.
Because the envelope holds the disk in place while the disk is being read, it is important that the dimensions of the jacket be maintained within very close tolerances. It is also critical that the folds be made accurately in order to assure that the folded envelope remains absolutely flat after the folds have been sealed. The task of folding these envelopes is further complicated when envelope holes are precut envelope blanks. The holes in such precut envelope blanks must be accurately aligned after folding is complete.
Because of these requirements, complex aligning systems have been provided in prior art machines to assure that the envelope blank is properly positioned at each folding station. Any misalignment of the envelope blank might render useless the final folded product. To prevent misalignment, prior art machines utilize one or more flat mandrils for holding the envelope blank while it is folded in half and while the side flaps are sealed. The mandril acts as a form and the jacket is folded around the mandril. Thus, any slight misalignment of the equipment will result in mis-shaped envelopes. Moreover, the mandrils are frequently used to transport the partially folded envelope blank to a gluing or heat sealing station, thus preventing insertion of disk media during the envelope folding operation.
In view of the above, it would be desirable to develop novel methods and systems for folding floppy disk envelopes to facilitate the proper placement of fold lines in the folded product. It would be particularly desirable if such methods and systems allowed for insertion of the disk media into the envelope during the folding process and complete sealing of the envelope before the folded product was discharged from the machine.